Lecture Notes: Autotrophs and Heterotrophs

Introduction

• Discussed favorite animals and plants.
• Importance of knowing what your favorite animal eats.

Heterotrophs

• Definition: Organisms that consume organic matter.
• Includes:
  • Animals (e.g., carnivores, herbivores, omnivores)
  • Fungi
  • Some protists, bacteria, and Archaea.
• Termed as consumers.

Autotrophs

• Definition: Organisms that make their own food.
• Generally plants and some protists, bacteria, and Archaea.
• Use inorganic substances to create organic substances (e.g., glucose from carbon dioxide).
• Termed as producers.

Special Cases

• Carnivorous Plants: Autotrophs that also digest insects for nitrogen.
• Euglena: Can be both autotrophs and heterotrophs.

Carbon and Energy Sources

• Autotrophs: Use inorganic carbon sources.
• Heterotrophs: Obtain carbon from organic sources.

Photo and Chemo Prefixes

• Photo: Energy source is light.
• Chemo: Energy source is chemical.

Types of Organisms Based on Energy and Carbon Sources

• Photoautotrophs: Use light as energy source (e.g., plants).
• Chemoautotrophs: Use chemicals as energy source (e.g., bacteria near deep sea vents).
  • Example: Bacteria that oxidize hydrogen sulfide.
• Chemoheterotrophs: Use organic compounds as energy source (e.g., humans).
• Photoheterotrophs: Light as energy source but consume organic matter (found in some prokaryotes).

Cellular Respiration

• Process to break down food into ATP.
• Varies across organisms (oxygen usage, electron acceptors).

Conclusion

• Fascination with the diverse ways organisms obtain nutrients.
• Encouragement to stay curious.